The invention relates to a device and a process for excavating and backfilling of soil, in particular for laying of pipes in ditches.
When ditches are excavated, in particular for the purpose of laying pipes, excavators are used which comprise a pivoted excavator bucket at the end of a boom. The boom is made up of a plurality of boom arms connected to each other with hinges, which allow a given movement of the excavator bucket controlled by an operator or a control unit. The ditches in which the pipes are laid are approximately 3 m deep and approximately 1.20 m wide.
During conventional laying of pipes first the ditch is dug and the excavated material transported to a dump site. Then a supporting layer for the pipes is prepared in the soil and the pipes are embedded up to at least half their diameter in a grit or gravel layer.
Filler capable of being packed is supplied, fed into the ditch and packed. The ditch is then filled with crushed stone and covered with asphalt, if necessary.
This procedure presents several drawbacks. Removal of the excavated soil and dumping of the excavated material on a dump site involves costs of approximately DM 40/m.sup.3. From the ecological point of view dumping of the soil is unnecessary. Further costs arise for the filler supplied. Furthermore, removal and delivery of the materials by truck require thorough logistic planning. The site must be cordoned-off to a large extent to control the truck traffic so that it is not possible to set up a small mobile site. Finally progress of work depends to a large extent on the traffic and that the waste is continuously removed in due time and the filler is continuously delivered in due time.